MRC Chips for the Audi urS-cars

Stage 3 Chips (RS2)

Chips plus VMAP
These Stage 3 chips, for use in the 4A0 907 551 AA ECU (AAN engine in the 1992-1997 Audi S4 and S6 models) and usually referred to as RS2 level chips, require added modifications to work their magic on the AAN engine. These mods include the RS2 (or equivalent) turbocharger, the RS2 exhaust manifold, and higher flow injectors.

Fuel
Generally, our RS2 level chips are designed for use with 93+ octane [(R+M)/2] fuel. If 93 is not available in your area chips for either 92 or 91 octane fuel are available at no extra cost. Chips for 100 octane fuel are also available (at extra cost) for track use.

Injectors
The injectors usually associated with “RS2” are quite expensive. We have identified two alternative injectors, Lucas/Delphi 37#/hr injectors and 034 Replica RS2 injectors which are significantly less expensive than the “usual” RS2 injectors and which are capable of even greater flow rates than the RS2 injectors. These different flow characteristics require different fuel control software. Prices on these injectors run in the $35 to $55 each range as compared to well over $100 each for the RS2 injectors. You will need a set of five injectors. There have been reports of mixtures being too rich with certain examples of the L/D injectors therefore it is suggested that the 034 injectors may be a better choice. If, on the other hand, you already have RS2 injectors we can provide the correct software for these as well. We just need to know which injectors you will be using.

MAF
Commonly a specific RS2 Mass Air Flow detector is used for RS2 mods. We have determined that, though the labeling indicates a difference between the RS2 MAF and the stock AAN MAF, electrically they are identical and therefore a special RS2 MAF is unnecessary. This allows you to keep your original MAF – again at a considerable saving.

FPR, etc.
Often RS2 mods specify a certain Fuel Pressure Regulator for use with the RS2 injectors. Again, we find this is unnecessary when using the Lucas/Delphi injectors and software designed to accommodate these injectors.

Performance
Look for power levels in the 360 to 380 hp range. It will put a smile on your face. Maximum boost levels will reach 25 to perhaps 27 psig.

Hoses
Increasing maximum boost levels from about 14 to 15 psig to 26 or so psig can put significant stress on ten plus year old rubber hoses. A blown hose can leave you at the side of the road unless you are handy at roadside repairs and have the necessary supplies in the car. For this reason it is recommended that you install sturdy silicon hoses for the high pressure side of the induction system. Samco hoses are excellent for this purpose. These hoses are available through a number of sources. ECSTuning is one of them.

Here is a tip I picked up recently. Not having tried it myself I can't attest to its value but... When installing Samco hoses lubricate the hoses and the pipes they are going onto with hair spray. This will help the hose to slide over the pipe and, when the hair spray sets, will act as an adhesive to help the hose stay in place under boost. I haven't tried it but it sounds reasonable. Of course this would not substitute for decent clamps for the hose connections.

Intercooler
Our normal chips are designed to make use of the OEM intercooler (IC). A number of our clients have replaced the OEM IC with a larger and more efficient Front Mounted Intercooler (FMIC). The FMIC is better able to cool the charge air before it enters the cylinders. This makes the air more dense and allows more air and fuel to be used. This permits advancing timing a little more than is possible without the FMIC. We can provide chips which will accommodate an FMIC but we need to know of the presence of the FMIC if you have or are getting one.

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